When neither high purpose nor the categorical imperatives of religion will do, the only argument against suicide is life itself. You pause and attend: the heart beats in your chest; outside, the trees are thick with new leaves, a swallow dips over them, the light moves, people are going about their business.
How interesting it would be to write the story of the experiences in this life of a man who killed himself in his previous life; how he stumbles against the very demands which had offered themselves before, until he arrives at the realization that he must fulfill those demands. The deeds of the preceding life give direction to the present life.
Irrevocable commitment to any religion is not only intellectual suicide; it is positive unfaith because it closes the mind to any new vision of the world. Faith is, above all, openness - an act of trust in the unknown.
We know that to wage a nuclear war today, for example, would be a form of suicide; or that to pollute the air or the oceans in order to achieve some short-term benefit would be to destroy the very basis for our survival.
He must not merely cling to life, for then he will be a coward, and will not escape. He must not merely wait for death, for then he will be a suicide, and will not escape. He must seek his life in a spirit of furious indifference to it.
I do see that there is an argument against suicide: the grief of the worshipers left behind, the awful famine in their hearts, these are too costly terms for the release.